@Evan: because I'm underweight, I am about 60 kilograms, which is like 135 pounds? and I'm 5'9.

hmmm casey, depends on which exercise.Uhm a for example in bench press I can now lift like 20 kilos (45 pounds?)In the seated chest press I can do about 45 (not sure if kilos or pounds but I think thats also in kilos).Before these 6 months I've never been to a gym, I just played some basketball.